A few people have said that they have received credit (in error) for their second room. It's not supposed to happen but you might get lucky.

As for getting checked out of the room, you can just mention it to the FD or staff if it's just a couple days. There's nothing wrong with leaving your stuff and keeping your room for a few nights on a long stay and that way there's no chance you get checked out (although I think the risk would still be very low either way)